ERBB2 and breast cancer: Several large clinical studies conducted by multiple groups indicate that anthracycline-containing regimens only incrementally benefit the ∼25% of breast cancer patients that have HER2 amplification or overexpression over non-anthracycline-containing regimens (Muss et al, 1994; Paik et al, 1998; Thor et al, 1998; Dressler et al, 2005; Piccart-Gebhart, 2006; Pritchard et al, 2006; Gennari et al, 2008).